Functionalized Fluorescent Nanocrystal Compositions and Methods for Their Preparation

• US 20100291702A1
• Filed: 03/13/2007
• Published: 11/18/2010
• Est. Priority Date: 09/17/2001
• Status: Active Grant

• Current Assignee: Life Technologies Corporation (Thermo Fisher Scientific Incorporated)
• Original Assignee: Invitrogen Corp. (Thermo Fisher Scientific Incorporated)
• Inventors: Naasani, Imad
• Granted Patent: US 8,283,179 B2
• Time in Patent Office: Days
• US Class Current: 436/172
• CPC Class Codes: B82Y 15/00 Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
• CPC Class Codes: G01N 33/588 with semiconductor nanocrystal label, e.g. quantum dots
• CPC Class Codes: Y10T 428/265 1 mil or less
• CPC Class Codes: Y10T 428/2982 Particulate matter [e.g., sphere, flake, etc.]
• CPC Class Codes: Y10T 428/2989 Microcapsule with solid core [includes liposome]
• CPC Class Codes: Y10T 428/2991 Coated
• CPC Class Codes: Y10T 428/2998 including synthetic resin or polymer

Abstract

The present invention provides for functionalized fluorescent nanocrystal compositions and methods for making these compositions. The compositions are fluorescent nanocrystals coated with at least one material. The coating material has chemical compounds or ligands with functional groups or moieties with conjugated electrons and moieties for imparting solubility to coated fluorescent nanocrystals in aqueous solutions. The coating material provides for functionalized fluorescent nanocrystal compositions which are water soluble, chemically stable, and emit light with a high quantum yield and/or luminescence efficiency when excited with light. The coating material may also have chemical compounds or ligands with moieties for bonding to target molecules and cells as well as moieties for cross-linking the coating. In the presence of reagents suitable for reacting to form capping layers, the compounds in the coating may form a capping layer on the fluorescent nanocrystal with the coating compounds operably bonded to the capping layer.

Claims

1. A functionalized fluorescent nanocrystal comprised of:

a fluorescent nanocrystal; and

a coating material comprised of a heteroaromatic compound.

2. The functionalized fluorescent nanocrystal of claim 1, wherein the fluorescent nanocrystal emits light with a quantum yield of greater than about 10%.

3. The functionalized fluorescent nanocrystal of claim 1, wherein the fluorescent nanocrystal emits light with a quantum yield of greater than about 50%.

4. The functionalized fluorescent nanocrystal of claim 1, wherein the heteroaromatic compound is selected from the group consisting of thiazole, thiazole derivatives, oxazole, oxazole derivatives, pyrrole, pyrrole derivatives including doped or undoped poly-pyrrole oligomers, thiophene, thiophene derivatives including doped or undoped poly-thiophenes, furan, furan derivatives, pyridine, pyridine derivatives, pyrimidine, pyrimidine derivatives, pyrazine, pyrazine derivatives, triazine, triazine derivatives, triazole, triazole derivatives, phthalocyanine, phthalocyanine derivatives, porphyrin, and porphyrin derivatives.

5. The functionalized fluorescent nanocrystal of claim 1, wherein the heteroaromatic compound is substituted with a group selected from unsaturated (olefin) hydrocarbons, acetylenes, propynes, and allenes.

6. The functionalized fluorescent nanocrystal of claim 1, wherein the fluorescent nanocrystal is soluble in a fluid with a surface energy of greater than 35 dynes/cm.

7. The functionalized fluorescent nanocrystal of claim 1, wherein the fluorescent nanocystals are soluble in an aqueous solution.

8. The functionalized fluorescent nanocrystal of claim 1, wherein the coating material is bound to a molecular probe.

9. The functionalized fluorescent nanocrystal of claim 8, wherein the molecular probe is a polynucleotide of known sequence.

10. The functionalized fluorescent nanocrystal composition of claim 8, wherein the molecular probe is selected from the group consisting of avidin, ConA, lectin, and IgG.

11. The fluorescent nanocrystal of claim 1, wherein the nanocrystal is a doped metal oxide nanocrystal.

12. The fluorescent nanocrystal of claim 11, wherein the doped metal oxide nanocrystal that is magnetized when irradiated with light.

13. The functionalized fluorescent nanocrystal of claim 1, wherein the fluorescent nanocrystals have a characteristic spectral emission intensity which is enhanced by the coating material.

14. The composition of claim 1, wherein the fluorescent nanocrystal comprises a core material and a capping layer.

15. The composition of claim 14, wherein the heteroaromatic compound is operably bound to the capping layer.

16. The composition of claim 1, wherein the coating material further comprises a phosphine cross-linking compound.

17. A method for detecting a target species, the method comprising:

exciting a complex formed by operably bonding a fluorescent nanocrystal to a target molecule to form a complex wherein the fluorescent nanocrystal includes a coating material comprising a heteroaromatic compound; and

detecting the light emitted from the complex.

18. The method of claim 17, wherein the detecting further comprises detecting the intensity of light emitted from the complex in the perpendicular and parallel directions.

19. A process for the preparation of a functionalized nanocrystal comprising contacting a fluorescent nanocrystal comprising a core material and a capping layer with a heteroaromatic compound to form a coating material on the fluorescent nanocrystal, wherein the heteroaromatic compound is operably bound to the capping layer.

20. The process of claim 19, further comprising contacting the fluorescent nanocrystal with a phosphine cross-linking compound.